Conventionally, video quality assessment is basically so-called subjective quality assessment, which measures the quality perceived by a user when he/she actually observes a video. Subjective quality assessment, however, requires a dedicated facility and enormous time and labor. Demands have therefore arisen for objective assessment methods of estimating subjective qualities from the amounts physically measured from videos to perform video quality assessment more efficiently.
According to a conventional objective assessment method, it suffices to handle a stable signal for professional use, e.g., a signal for a broadcasting station, as a target video signal, and only an objective assessment algorithm is determined for standardization, as described in, for example, reference “Objective Perceptual Video Quality Measurement Techniques for Digital Cable Television in the Presence of a Full Reference”, ITU-T Recommendation J.144, 2004”.
For this reason, in matching processing to be performed before the estimation of the subjective quality of a degraded video signal, matching between the degraded video signal and a reference video signal can be implemented by performing the format conversion processing of matching the format of the degraded video signal with that of the reference video signal before degradation and the position/synchronization matching processing of matching the time and position of the degraded video signal with those of the reference video signal (see, for example, the specification of U.S. Pat. No. 5,446,492).